The construction material of choice for modern multi-story structures is concrete. A durable material, and readily available around the world, it can be used to form floors, walls, and columns that eventually result in a complete building.
Conventional cast-in-place concrete construction relies on the use of labor-intensive, time-consuming, bulky, built-in-place formwork that must be erected for each wall and column. The formwork takes up space that could be used for moving around the site in the floor below, and does so for the duration of the construction. This process alone is time-consuming. After the formwork is placed, concrete is poured within the forms. This concrete is allowed to partially cure, then the formwork is removed and after twenty-eight days, the concrete can bear its full load. The result of these delays is the slow the speed of construction.
Given the time-consuming nature of cast-in-place concrete, the concept of casting off-site arose, with the pre-cast concrete pieces then being assembled on-site. While moving the slow and time-consuming process of pouring concrete and wait for cure, to an off-site location, does speed up the process of construction, the resulting structure lacked the strength of a cast-in-place building due to weak connectivity. Additionally, because the pre-cast concrete must be transported to the construction site, the panel size is limited. The result is a building made from many separate panels that fail to transfer loads to adjacent bays as in the case of poured-in-place structures.
What is needed is a system for constructing a building that combines the strength and continuity of cast-in-place construction with the rapid assembly of precast construction, thus maintaining structural continuity between bays and floors by redistributing stresses to adjacent bays, while simplifying the process of casting the pre-cast pieces and reducing the transportation requirements of the resulting pieces.